Agricultural harvesters use row units for separating ears of corn from plant stalks. Row units are disposed along the leading edge of a harvesting head, and the harvesting head is mounted to the harvester vehicle portion of the agricultural harvester. Row units typically include two forwardly extending, rotating stalk rolls.
Stalk rolls are usually arranged as adjacent elongated cylinders and mounted on elongated rotating shafts. Such an arrangement forms a narrow space between the stalk rolls. The stalk rolls receive the plant stalk in the narrow space that is formed between the stalk rolls. As the stalk rolls rotate, they grasp the plant stalk and pull it downward using knife edges. Then, a stripper plate, disposed above the stalk rolls, pulls ears of corn from the plant stalk. Subsequently, the ears of corn are conveyed rearward, leaving room for the stalk rolls to receive another plant stalk.
Protrusions disposed on the outside surfaces of the stalk rolls perform the grasping operation just mentioned. Typically, the protrusions are in the form of knife edges. Such edges grasp the stalk by penetrating into it and pulling it downward. This contact, between the stalk and the stalk rolls, creates significant wear on the knife edges.
The applicants have identified a wear pattern that is common to many knife edges: the wear at the front and rear portions of the knife edges fends to be greater than the wear at the central portions. This pattern is due to the nature of the stalk segments that are grasped at each portion along the knife edges.
At the front portions, where the stalk rolls first grasp the base segments of the stalks, the stalks are large in diameter and contaminated with dirt and minerals. Thus, there is usually more wear on the front portions of the knife edges than on the middle portions. At the central portions, as the stalks are pulled downwards and backwards along the length of the knife edges, the stalks are smaller in diameter and cleaner. This is why there tends to be less wear on the central portions. At the rear portions, the knife edges must sometimes grasp and pull down longer segments of the stalks than the front and central portions must poll down. Because of this, there tends to be more wear on the rear portions than on the middle portions.
The applicants propose to provide an optimum wear coating on each knife edge that addresses this nonlineariiy of wear and reduces costs. It is an object of this invention to provide such a wear coating.